We evolved to have that response in a world in which hospitals didn't exist and in which we faced predation by other animals, and 'curl into a ball feeling like shit for a couple days' was the most viable way for the body to handle even the most mundane of infections (all the other ideas didn't make the cut and here we are). But now, 21st century, we're like 'oh it's just the cold' and actively attempt to mitigate it.

A slew of other things are still stuck in 20,000BC as well, like our bodies not being able to deal with copious amounts of sugar, or thinking we might have difficulties securing our next meal. Cut too many calories trying to lose some fat and your body legit thinks you're dying and starts breaking down all sorts of soft tissue that isn't fat. Or vasoconstriction when we're out shoveling snow with a warm house 15ft away, all sorts of shit